From: David Howells <dhowells@redhat.com>
To: Keith Owens <kaos@ocs.com.au>
Cc: "Randy.Dunlap" <rddunlap@osdl.org>,
Jim Nelson <james4765@cwazy.co.uk>,
Alan Cox <alan@lxorguk.ukuu.org.uk>,
Coywolf Qi Hunt <coywolf@gmail.com>,
Jesper Juhl <juhl-lkml@dif.dk>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: printk loglevel policy?
Date: Tue, 04 Jan 2005 10:46:45 +0000 [thread overview]
Message-ID: <2583.1104835605@redhat.com> (raw)
In-Reply-To: <28707.1104722227@ocs3.ocs.com.au>
Keith Owens <kaos@ocs.com.au> wrote:
> >That kind of garbled output has been known to happen, but
> >the <console_sem> is supposed to prevent that (along with
> >zap_locks() in kernel/printk.c).
>
> Using multiple calls to printk to print a single line has always been
> subject to the possibility of interleaving on SMP. We just live with the
> risk. Printing a complete line in a single call to printk is protected by
> various locks. Print a line in multiple calls is not protected. If it
> bothers you that much, build up the line in a local buffer then call printk
> once.
The oops writer breaks the locks. It's _really_ annoying when oopses happen
simultaneously on separate CPUs - the oops reports end up interleaved
char-by-char.
My patch serialised oops writing.
David
prev parent reply other threads:[~2005-01-04 10:47 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-12-31 2:02 [patch] add loglevel to printk in fs/afs/cmservice.c Jesper Juhl
2004-12-31 2:20 ` printk loglevel policy? Coywolf Qi Hunt
2004-12-31 4:07 ` Jim Nelson
2004-12-31 4:34 ` Jesper Juhl
2005-01-02 14:36 ` Alan Cox
2005-01-02 19:01 ` Jim Nelson
2005-01-02 21:41 ` Randy.Dunlap
2005-01-03 3:17 ` Keith Owens
2005-01-03 3:52 ` Randy.Dunlap
2005-01-03 4:44 ` Jim Nelson
2005-01-04 10:46 ` David Howells [this message]
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